Valve for rock drills



June 3, 1930. I E B. LEAR 1,761,134

VALVE FOR ROCK DRILLS' Filed April 6, 1927 2 Sheets-Shee t 1 INVENTOR.

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JunB, 19 30. E. B. LEAR 1,751,134

VALVE FORROCK DRILLS Filed April 6, 1927 v 2 Sheets-Sheet 2 i m/ f wimy W WWW X IN V EN TOR.

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Patented June 3, 1930 wires STATES I EARL 1B. LEAR, or rmnnrrssnns,*nnw annsnn nssrenon TO meEnso nnann-coM- 'P NY,.orannsnyc r ,'nnwlmnsnv, n'conronnrroncr new JERSEY VALVE ron RGGK IfiHLL'S Application fil pril c,

This invention relatesto i601; drills, but more particularly to a distributing valve for fluid actuated rock drillsof the hammer type.

V The objects .of the invention areto obtain rapid distribution of the pressure fluid to the cylinder and to obtain a'positive action of the valve. 7 i I ,ther objects will appear hereinaftenanol to all of these'ends the invention consists of the combination of elements and arrangement of parts having the general mode ofsoperati-on substantially as hereinafter described and claimed and illustrated int-the accompanying drawings in which: i I r Figure 1 is a longitudinal sectional V ew of a rock drill showing the valve in posit on to admit air to the rearwardend of the cylinder,

Figure 2 is alongitudinal sectional elevation of the valve chest and a portion of the cylinder illustrating the manner in which the valve is actuated, and V Figure 3 is a view similar to Figure 2 show-- ing the valve in position to admit pressure fluid to the front end of thecylinder.

Referring to the drawings, A designates a cylinder and B a hammer piston reciprocable in the cylinder. A'closure is provided for the front end of the cylinder in the form of a bushing C which forms an abutment for a front head D. At the rearward endvof the cylinder is disposed a plate'E which forms a closure for the rearward end of the cylinder and is recessed as at F to centralize a rotation ring Gr on which is seated a back head H. The rotation ring may be of a well known type adapted to cooperate with spring pressed pawls J carried by a rifle barK for holdlng said rifle bar stationary to impart rotary movement to the piston B which it engages in a well known manner. v

The drill is provided with the usual water and air tubes L and 0 respectively for conveying cleansing liquid and pressure fluid from the back head to a working implement P which extends into the front head to receive the blows of the hammer piston B, such blows in this instance being transmitted through an anvil block'Q, in the front head D. A water plug R screwed into the back ,9 constitute {actuating surfaces against which 1927. Serial No.- 181,424. 7

head cooperateswith the tubes and bore T,said bushing is provided with a flange Y at itsrearw'ardend to'seatin a recess Z formed in the end of the bore T. The rearwardor outer end of-the bushing U is preferably formediflush with the corresponding end of the valve chest Sto enablethe-plateE tobear thereon for holdingvthe bushing U against longitudinal movement. 1

"The bushings U and ;V,are provided with Thedbushing Vis provided withfa stem 1, vbores bsa'nd cfrespectively to' form ,a.Va1.veW

chamber for a pressure fluid distributing valved In the present instance the bores 37 and'c are formed'of three diameters, the larger vdiameters e of which are located at the inneror adjacent ends of-the bushings. The intermediate portions f of the bores 2b and c are, of somewhat smallerdiameter'than ,the portions 6 and at the outer'ends of the intermediate portions f are formed vrecesses g of smaller diameter than theportionslf toreceive the reduced ends iifof the valved.

As will bev observed, the valve cl is provided with a bore j whichextends throughout the length of the valve. The borej is in constant communication with the. pressure fluid sup -ply (notshownithrougha passage. lain .the V formed an cnlarged flange g which controls 1 an exhaust p-orto" in the valvechest S. The

rearward andfront 'face's s and t of-z-the flange intermediate the ends of the valve .(if is pressure fluid issuing from rearward and 'front exhaust passages wand 41 respectively ,from the cylinder to the valve chamber I wherewith they communicate at points on in its forward limiting position, the pressure opposite sides of the exhaust port 9".

In the construction shown the pressure fluid for impelling the piston B forwardly flows over the front end of the valved and through an inlet passage w leading to the rearward end of the cylinder A. In like manner pressure fluid flows over the rearward end of the valve (Zthrough an inlet passage m leading from the rearward end of the valve chamber to the front end of the cylinder for impelling the piston B in a rearwardly direction.

Suitable means are'provided for insuring against trembling of the valve (Z after it has been thrown to its limiting positions. To that end the valve is provided at its rearward end with a shoulder 3 against which pressure fluid may act for holding the valve forwardly while the pressure fluid is being admitted to the front end of the cylinder. Similarly, a shoulder a is formed near the front end of the valve and is subjectedto live pressure fluid for holding the valve rearwardly while pressure fluid is being admitted into the rearward end of the cylinder.

The operation of the device is as follows: \Vith the valve in the position shown in Figure 1 pressure fluid flowing therethrough will pass over the front end thereof and through the inlet passage w into the-rearward end of the cylinder and actuate the piston 13 forwardly to. deliver its blow against the work ing implement. During the time pressure fluid is flowing to the rearward end of the cylinder the shoulder z of the valve will be exposed to such pressure fluid whereby the valve will be held "firmly" in its rearward limiting position.

Immediately prior to the delivery of the blow of the piston on the working implement the piston will uncover the exhaust passage wand thepressure fluid in the rearward end of the cylinder will then escape through the passage a into the valve chamber. The escaping pressure fluid acting against the actuating surface s will throw the valve forwardly to uncover the exhaust port 9' and will thence escape to the atmosphere through the exhaust port 1".

In the forward position of the valve pressure fluid will flow over the rearward end of the said valve through the inlet port 00 to g the front end of the cylinder to again drive the piston rearwardly. proaches the rearward end of the cylinder the forward exhaust passage 1) will be uncovered by the piston and the pressure fluid in the front end of the cylinder will flow through the said exhaust passage 0 into the valve chamber and, acting against the actuating surface t of the flange will again throw the valve (Z rearwardly to its initial position, vthus completing the cycle of operations.

It will be observed that while the valve is As the piston ap-' fluid admitted into the inlet passage w will also act against the shoulder g of the valve to hold the valve firmly in its forwardmost position.

I claim: 1

'In a fluid actuated rock drill, the combination of a-cylinder and piston, a valve chest having a valve chamber, crossed inlet passages leading from the valve chamber to the cylinder, an exhaust port in the valve chest, a hollow distributing valve through which the live motive fluid passes to the inlet passages, said valve having a central enlarged flange to control the exhaust port, actuating pressure areas on the flange, enlarged portions at the ends of the valve forming shoulders having holding pressure areas and reduced end extensions extending from the body of the valve, the valve chest being formed with recesses for receiving said extensions, the live motive fluid passing over the ends of the valve to each end of the cylinder and thereby producing holding pressure on that one of the holding areas subjected to live motive fluid, and exhaust passages for exhausting pressure fluid from the cylinder into the valve chamber to act against the actuating pressure areas for throwing the valve and opening the exhaust port to permit the escape of pressure fluid from the valve chest to the atmosphere. I

In testimony whereof I have signed this specification.

EARL B. LEAR. 

